VMS Help CC, Run-time functions, Curses  *Conan The Librarian (sorry for the slow response - running on an old VAX)

  Curses, the Compaq C Screen Management Package, is comprised of RTL
  functions that create and modify defined sections of the terminal
  screen, and optimize cursor movement.  Using a screen management
  package, you can develop a user interface that is both visually
  attractive and easy to use.  Curses allows you to manipulate the
  screen without worrying about the intricacies of various types of
  terminals, the difficulties of moving data to and from sections of
  the screen, or the problems of efficient cursor movement.

  Using Curses, the terminal screen may be divided into a number of
  rectangular regions called windows.  The size and location of each
  window is given in terms of the number of lines, the number of
  columns, and the starting position -- the upper left corner of the
  window.  A window must fit completely on the terminal screen, being
  as small as a single character or as large as the entire terminal
  screen.  When modifying windows, changes will not appear on the
  terminal screen until the window is refreshed.  When a window is
  refreshed, the updated window is placed onto the terminal screen
  leaving the rest of the terminal screen unaltered.